Approaching an 85-mph corner at 150 mph, I’m glad my stomach is calm and my bladder is empty. The Audi R8 GT4 race car has a surprising number of nooks and crannies to hold and hide any substances that may escape my body, and my brain has enough to think about already without working a hefty cleaning bill into my finances.
I need all the mental bandwidth I can get because I’m tearing around the 24 turns of Southern California’s Thermal Club circuit. I’m doing it to see not what this Audi can do but what it can tell me.
In racing, just like in the rest of the modern world, skill matters. But it doesn’t matter much if you don’t have the data that can inform your every move. That’s why, in a 30-minute track session, the R8 GT4 logs up to 28 megabytes of data on engine performance, gearbox operation, steering, throttle and brake application, and the myriad chassis variables available to the racing team’s computers. And this is the little brother. The R8 GT3 (which costs twice as much, at about a half-million dollars) stacks up 2 to 3 gigabytes of data in the same amount of time.
And you need all that data. But more importantly, you want all of it, whether you’re a pro, a rookie, an engineer, or an engine control computer trying to keep your mechanical client from blowing itself up.
Forget football, golf, tennis, or any other sport (except perhaps America’s Cup yacht racing). Professional auto racing—from Formula 1 to Nascar to IndyCar—is the ultimate strategy and calculations pastime. As a driver, you’re constantly processing digital data off the car, studying the action in front of you, calculating when to pit for fuel or a tire change, adapting to weather conditions, and making a thousand other calls. Data informs all that.
The R8 GT4 goes through so much data, it needs a second wiring harness just to support the onboard logger and dash display. “We can log data from about 120 channels in total,” says Audi Customer Racing’s electronics guru, Cody Ragone. “We can tap multiple channels for the engine alone, like fuel pressure, fuel use, ignition advance, Lambda sensor, throttle position, exhaust temps, orientation of the camshafts and, of course, crankshaft position.”
Just enough to make the R8 GT3 chuckle. The bigger, more expensive car can log data in 2,500 channels—it needs a customized, military-grade harness and an engine computer that costs $20,000, compared to the $1,000 unit that comes stock. As with many things in life, it’s a sliding scale of cost and complexity. And speed.
“Some channels only need low-res sampling,” says Ragone. Coolant temperature does not change rapidly, so one to two times per second is fine. But shock absorber position sensors must be logged much more frequently to be useful. “We’re likely logging at 500 to 1,000 Hertz.” Now multiply that by four, for each corner of the car.
“For the big professional teams, in addition to engine, transmission, braking and steering data, we use linear potentiometers on the shocks, laser ride-height sensors and wheel hub accelerometers,” Ragone says. “With all that high-resolution information, we need very high logging rates for the large volume of data, often up to 28 total megs of data over a session of 30 to 60 minutes.”
All that data helps engineers keep an eye on their creations. It can also turn a great driver into a masterful one—or paint a sober digital picture of one’s shortcomings. Corner entry and corner exit speeds, maximum braking pressure, distance under braking, centripetal forces from cornering, braking and acceleration, steering angle, yaw, top straightaway speed. These and about 30 other data points make up a report card stuff you may not want to show anyone. It’s also a guide for doing better.
“The more information we have, the better, especially for new drivers,” says Brad Kettler, Audi’s Customer Racing Chief. “Having the visualization of the data right after they come off the course in practice is mega.” Coaches can show such rookies where they’re going wrong and track their progress from one lap, or weekend, or season to the next.
It’s a major improvement over the old days (those ending in the early 2000s), when coaches relied on what drivers told them and data from the zip ties wrapped around shock absorber pistons that provided an analog visual reference on maximum suspension travel, which they’d read during pit stops. “It all seems quaintly primitive now,” Kettler says. “But that’s really what we used.”
For my track day, I had pro racer Jeff Westphal as a coach. He used the data returns from his best lap to guide me around the track: where I could brake later and harder; where I might hold or advance a shift in relation to a corner; where applying more throttle earlier exiting a corner would result in faster top speed at the end of that straightaway.
We debriefed after each session, looking at a paper track map, computer printouts of my data (throttle position, brake pressure, steering angle, vehicle yaw and acceleration, and so on), plus in-car video. Each time, I could see where I was getting better, and where I was leaving time on the table.
Racing mechanics have made incredible advances in recent years: carbon brakes, sequential twin-clutch gearboxes, vastly more sophisticated and elaborate shocks, tires that generate astounding grip. But Global Motorsports Group crew chief Neville Agass says this is not the greatest area of change.
“Mastering the digital is the real revolution,” he says. With sensors and computers managing everything about combustion including ignition, throttle, fuel mapping, averting detonation, controlling variable inlet manifolds, cam phasing, all the way to the engine preventing its own demise is all managed digitally.
“As a crew chief or mechanic, I now touch none of that,” he laughs. Years ago, the crew chief controlled all of those elements. But none of the speed now involved in digital control was possible—or even conceivable—when he was still driving. “Guesswork is completely history.”
Beyond telling you how to drive, all these points of data create a rolling health report for the car, which is also smart enough to cure various ills. Say the coolant is overheating, or the front and rear wheel speed sensors disagree on the car’s speed, or debris in the intake is blocking airflow. Rather than risk a catastrophic failure (and bill), the computer forces the engine into limp mode, allowing just enough power to get it to the pit lane. Electronics—with the help of data—save the mechanical.
Happily, the GT4 I was taking around the track at Thermal didn’t need to save itself from disaster, and I saved myself from the embarrassment of barfing in my helmet. Even better, I came away a more skilled driver—and knowing that skill isn’t always enough.